int randomNumber[4], guessNumber[4];
    srand((unsigned)time(NULL));
    again:for(int i = 0; i < 4; i++)
    {
        randomNumber[i] = rand() % 10;
        echo(randomNumber,i);
    }
    int count = 0;
    for(int i = 0; i < 4; i++)
    {
        cout << randomNumber[i];
    }
    while(count <= 20)
    {
        cout << "Please enter an number : ";
        int InputNumber;
        cin >> InputNumber;
        for(int i = 0; i <= 3; i++)
        {
            guessNumber[i] = InputNumber % 10;
            InputNumber = InputNumber / 10;
        }
        int A = 0, B = 0;
        for(int i = 0; i < 4; i++)
        {
            for(int j = 0; j < i; j++)
            {
                if(guessNumber[j] == randomNumber[i]) B++;
            }
        }
        for(int i = 0; i < 4; i++)
        {
            if(guessNumber[i] == randomNumber[i]) A++;
        }
        if(A == 4){
            cout << "Congrations!" << endl;
            break;
        }
        else{
            count++;
            cout << A << "A" << B << "B" <<endl;
        }
    }
    char Input;
    cout << "Do you want to play again?(Y/N) : ";
    cin >> Input;
    if(Input == 'Y') goto again;
    else exit(0);
}
void echo(int *randomNumber, int n)    //检测数字是否重复
{
    for(int i = 0; i < n; i++)
    {
        if(randomNumber[i] == randomNumber[n])
        {
            randomNumber[n] = rand() % 10;
            echo(randomNumber,n);
        }
    }
}